An apparatus 100 is described for precision volumetric metering and distribution of solid inputs used in agriculture, the apparatus being coupled to sowing devices and comprising a frame 1 with a through-hole 12 through which an axle 3 radially locked to a turbine 4 extends, the axle 3 driving the metering turbine 4; an opening 21 in the floor of the frame leads the agricultural input 31 to the output nozzle 13. The geometry of the turbine 4 comprises cutouts of various shapes which form chambers 5 for distributing the agricultural input 31 uniformly. A labyrinth 25 is formed by the frame 1, the inner grater 6 and the turbine 4. The structural geometry of the turbine 4 only allows metering of the input 31 while the turbine is rotating, while the agricultural input 31 is retained inside and on the turbine 4 when the turbine does not rotate.